Different types of biological samples (skin fibroblasts and skeletal myoblasts, different human biopsy specimens of patients with rare inherited metabolic diseases) have been collected, isolated, analyzed, stored and distributed for many years in Clinical Unit for Hereditary Metabolic Diseases, Department of Laboratory Diagnostics, University Hospital Center Zagreb. Fibroblast and myoblast cell cultures provide the possibility of in vitro research of numerous properties of connective tissue and muscular cells, which is particularly important in elucidating many congenital and acquired diseases, for understanding of physiological processes in the body, and as a precondition for studying many medications. Biological samples are stored in different biobanks and are necessary for diagnostics and research in every medical field, particularly in the field of rare diseases. At EU level, considerable differences have been observed in implementation of applicable directives, which is an additional problem in utilization of samples stored in biobanks and which consequently reduces public health benefits from such sample collections. For this reason, this graduation thesis describes optimization of methods for collection, culture, storage, and distribution of human fibroblasts, skeletal myoblasts and muscle biopsy specimens which open in Croatia new possibilities for diagnostics and research with the ultimate goal of creating preconditions for founding a tissue and cell biobank for rare diseases and its harmonization with European biobank.